load notifications from db
class NotifyConnectorPool

It looks like there's no where to hook code for saving notificaitons
to DB. We're going to have to keep consistent in real time.
Notify insert()/delete()

Allrighty, there doesn't seem to be any way around it.
Notifications will be stored in the SeaIce database so that
dangling notifications can be deleted on term remove cascade.
Added notify transactions to SeaIceConnector
Purged NotifyConnector